Law enforcement, paramilitary and military personnel typically carry advanced firearms systems for offensive and defensive activities. These systems include gas-operating rifles. Contemporary military technology includes the attachment of various accessories, including sights, illumination devices and other devices to the barrel of the firearm, notably to the hand grips along the barrel. Accessory mounts for weapons began with the development of the Weaver rail mount system that was the first standardized scope mount for rifles. The mount was improved in the 1980s and became the Picatinny rail system, a universal accessory system for military and paramilitary weapons. The Picatinny rail device has now relocated the foregrips on many military and paramilitary weapons systems. The foregrip is a handling structure located ahead of the firing action and along the barrel assembly of a modern firearm. The barrel assembly of a modern firearm typically includes a gas tube structure for the transfer of combustion gases from a forward port back along the barrel to a gas port located in the firing action assembly. The front end of the foregrip is nearer to the opening of the barrel. The rear or back end of the foregrip is closer to the firing action of the firearm. Today, one or more accessories can be mounted, including but not limited to tactical lights, laser aiming modules, night vision devices, reflex sights, foregrips, bipods and bayonets. Picatinny rails and accessories have relocated iron sights in the design of many firearms and are now incorporated into pistol frames and grips. Picatinny locking slot dimensions are standardized such that the slot width is 5.23 mm. The slot centers are spaced apart by 10.01 mm. Weaver slots are less standardized, but have a uniform slot width of 4.57 mm. Accessories can be attached and detached by sliding them onto the rail from one end or the other, by clamping with bolts, thumbscrews or levers; or onto the slots between the raised sections or the rails.
The various rail systems for firearms utilize the particular geometry of the firearm without alterations to the barrels or fixed mechanisms particular to the function of the weapon. For example, the foregrips of a Colt AR-15, M-4 family of carbines or similar weapon are held in place by tension springs that hold collars over locking shoulders on the ends of the grips. The rail system shape at the ends conforms to the basic hand grips so that it replaces the existing grips without requiring modification to the barrel assembly or upper receiver of the weapon and uses the existing tension spring collars.
U.S. patent application Ser. No. 13/919,604, entitled VEHICLE MOUNTED FIREARM LOCK (the teachings of which are incorporated by reference as a useful background information), teaches a system for locking down a firearm via its rail system. Such locks are provided with a receiving slot that is constructed and arranged to receive a portion of an accessory rail on a firearm. A disadvantage of such systems is that the disconnection of the rail from the firearm barrel group can lead to unauthorized removal of a secured firearm from the lock, albeit without the accessory rail portion retained by the lock. However, given that the accessory rail is a fungible and non-registered item, it is a small loss compared with the firearm in terms of value. The rail lock riser can work in conjunction with devices that secure the upper receiver to the lower receiver. It would be desirable to provide a device that supports an accessory rail within a firearms lock that cannot be readily removed from the firearm.